Ashcroft B400 User manual

Brand: Ashcroft

Model: B400

Type: User manual

Ashcroft B400 is a precision-built pressure switch designed for accurate pressure control in various industrial applications. It features a mechanical snap action switch for reliable operation. This versatile device can be used for pressure or vacuum operation with fixed or variable differential, making it suitable for a wide range of pressure control requirements. The B400 offers manual reset functionality for increasing or decreasing pressure, ensuring precise control and safety.

Installation and Maintenance Instructions for

B400 & B700 ASHCROFT®Snap Action

Switches for Pressure Control

INTRODUCTION

The Ashcroft pressure switch is a precision built agency

approved control device which features a mechanical snap

action switch. Controllers are available for operation on pres-

sure or vacuum with fixed or variable differential. Also manual

reset types for operation on increasing or decreasing pressure.

The manual reset types remain tripped until reset by pressing a

button on top of the enclosure. Standard electrical switch is

SPDT, available with various electrical characteristics. Two

SPDT switch elements mounted together are available except

on variable Deadband and manual reset types. Various wetted

material constructions for compatibility with a range of pressure

media may be obtained.

The Ashcroft snap action pressure switch is furnished in the

standard NEMA 4 and explosion-proof NEMA 7 & 9 enclosure

styles. Both enclosures are epoxy coated aluminum castings.

INSTALLATION

These controls are precision instruments and should never be

left with internal components exposed. During installation insure

that covers are in place and conduit openings are closed except

when actually working on the control.

MOUNTING B400 AND B700 SERIES

Three holes external to the enclosure for surface mounting.

Location of these holes is shown on the general dimension draw-

ing. They may also be mounted directly on pressure line using

the pressure connection. When tightening control to pressure

line, always use the wrench flats or hex on the lower housing.

ELECTRICAL CONNECTIONS

Remove cover

B400 Series – two screws hold cover to enclosure

B700 Series – cover unscrews

CONDUIT CONNECTIONS

Note – It is recommended that Teflon tape or other sealant be

used on conduit, bushing or plug threads to ensure integrity of

the enclosure.

B400 DIMENSIONS

B700 DIMENSIONS

1.8 lb

(.81 kg)

2.7 lb

(1.2 kg)

2.7 lb

(1.2 kg)

STANDARD RANGES

15, 30, 60, 100, 200, 400, 600 psi

1000, 3000 psi

30˝Hg vac.-0

STANDARD RANGES

10, 30, 60, 100, 150 ˝H2O

15˝H2O vac.-15˝H2O

All sales subject to standard terms and conditions of sale. I&M009-10008-10/00 (250-2246E) 06/15

5.11

129.8

4.00

101.6

3.31

84.1

3.25

82.6

Ø2.31

58.7

Ø.28

7.1

X3 HOLES

1/4 NPT

FEMALE

2.55

64.9 1.25

31.8

.25

6.4

2.75

69.9

2.51

63.8

3/4 NPT

FEMALE

Ø 5.12

130

3.50

88.9

2.78

70.6

1.38

35.2

3.25

82.6

.50

12.7

4.00

101.6 Ø .28

7.1

X3 HOLES

Ø .34

8.6

X2 HOLES

3.31

84.1

6.46

164

5.75

146.1

3.19

81.1

3.86

97.9

1.25

31.8

.25

6.4

2.55

64.9

2.75

69.9 3/4 NPT

FEMALE

1/4 NPT

FEMALE

BRACKET WHEN

"XBP" VARIATION

REQUIRED

5.20

(132)

3.62

(92)

2.18

(55)

0.32

(8)

4.37

(111)

1.37

(35)

Ø 0.28 x 3 HOLES

(7)

1.11

(28)

Ø 5.12

(130)

1.93

(49)

2.78

(71)

3.50

(89)

0.36

(9)

1.39

(35)

6.43

163

0.50

(13)

0.36

(9)

Ø 0.34 X 2 HOLES

(9)

Ø 3.90

(99)

0.03

(1)

3.58

(91)

0.31 (8)

5.62

(143)

3.06

(78)

1.22 (31)

1/4 NPT FEMALE

3/4 NPT

2 HOLES

BRACKET WHEN

REQUIRED "XBP"

VARIATION

1.93

(49)

5.20

(132)

3.62

(92)

2.18

(55)

0.32

(8)

4.37

(111)

1.37

(35)

5.73

(146)

Ø 0.28 x 3 HOLES

(7)

Ø 3.90

(99)

0.03

(1)

3.58

(91)

2.31

(59)

0.31

(8)

1.22

(31)

1/4 NPT FEMALE

3/4 NPT 2 HOLES

B400 Series standard – one 3

⁄

4˝ NPT conduit hole right side.

B700 Series standard – two 3

⁄

4˝ N PT conduit holes with one

permanent plug. NEMA 7 & 9 enclosures require proper conduit

seals and breathers as per the National Electrical Code.

B400 & B700 Series – XJL variation – two 3

⁄

4˝ NPT conduit

holes with two 3

⁄

4˝ to 1

⁄

2˝ NPT reducing bushings.

B400 Series – XJK variation – two 3

⁄

4˝ NPT conduit holes.

B400 SERIES

SPDT – Wire directly to the switch according to circuit require-

ments. On controls with pilot lights wire lights according to cir-

cuit diagram on inside of cover. See special wiring instruction

tag for single switches with two pilot lights and dual switches

with one or more lights.

2 SPDT – Dual switching elements consist of two SPDT switch-

es mounted together in a bracket. Switches are calibrated to

have simultaneous operation within 1% of range either on

increasing or decreasing pressure but not in both directions.

Wire directly to the front and rear switch according to circuit

requirements. Leads are provided on rear switch color coded as

follows:

Common – White

Normally Closed – Red

Normally Open – Blue

See SPDT instructions for pilot light hook-up.

When hermetically sealed switch elements(s) are supplied, the

lead color coding is as follows:

Common – White

Normally Closed – Red

Normally Open – Blue

B700 SERIES

SPDT – Wire directly to the switch according to circuit require-

ments.

2 SPDT – Wire to front switch terminal block (left) and rear

switch terminal block (right) as marked. Strip insulation 5

⁄

16˝,

insert in proper terminal connector and tighten clamping screw

to secure.

ADJUSTMENT OF SETPOINT

B400 & B700 Series – A single setpoint adjustment nut (7

⁄

8˝) is

located centrally at the bottom on the inside of the enclosure.

For accurate setpoint calibration, mount the switch on a cali-

bration stand, a pump or catalog No.1305 deadweight gauge

tester. A suitable reference standard such as an Ashcroft

Duragauge or Test Gauge is necessary to observe convenient

changes in pressure.

As received, the pressure switch will normally be set to

approximately 90% of the indicated range. Pressurize the

system to required setpoint and turn the adjustment nut until

switch changes mode. Direction of turning is indicated on a

label affixed to the inside of the control enclosure. When set-

point has been achieved raise and lower pressure to insure that

setpoint is correct.

SETPOINT LOCKING SCREW (B400 ONLY)

Once setpoint has been determined, tighten setpoint locking

screw using a 5/64˝ allen (hex) wrench. Do not over torque;

setpoint locking screw only needs to be hand tight.

When performing calibration or changing the setpoint, the setpoint

locking screw should be loosened before turning the setpoint

adjusting nut. Once calibration is complete, re-tighten the set-

point locking screw.

After installation of the control replace cover to insure electrical

safety and to protect internal parts from the environment.

B450 and B750 VARIABLE DEADBAND SWITCHES

Deadband is varied by rotating the wheel on the precision

switch. When viewed from the front of the enclosure, rotation to

the left increases deadband – rotation to the right decreases

deadband. Letters on the wheel may be used as a reference.

Deadbands obtainable will vary from 0.5% to 9% of pressure

range depending on range segment and type of diaphragm.

ADJUSTMENT OF SETPOINT

As received, the pressure switch will normally be set to approxi-

mately 90% of range. Rotate the wheel on the MICRO SWITCH

all the way to the right; this will provide smallest deadband.

Pressurize the system to the required setpoint and turn the

adjustment nut until the switch changes mode. Lower the

pressure to reset the switch. Rotate the wheel on the MICRO

SWITCH until the desired deadband is obtained. The upper

setpoint will be changing upward with this adjustment. Lower

the pressure to reset the switch. Then increase the pressure to

the desired setpoint and turn the adjusting nut until the switch

changes mode. Lower the pressure and check resetpoint and

deadband.

Note – As indicated above, adjustment of setpoint is made by

use of 7

⁄

8˝ nut. Precision switch element mounting

screws and bracket adjusting screw are factory sealed

and should not be tampered with.

Note – Since vacuum models are already above setpoint at

atmosphere, the Normally Open (NO) circuit will be

closed as received.

Recommended Practices

Ashcroft recommends regular inspection of the operation and

setpoint of the switch in critical applications to prevent issues

that could cause severe damage to personnel or property.

Installation and Maintenance Instructions for

B400 & B700 ASHCROFT®Snap Action

Switches for Pressure Control

TERMINAL BLOCK

SWITCH A

TERMINAL BLOCK

SWITCH B

All sales subject to standard terms and conditions of sale. I&M009-10008-10/00 (250-2246E) 06/15

Setpoint

Locking

Screw

Ashcroft B400 User manual

Ashcroft B400 User manual

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